This very precise drilling jig is designed specifically to guide the drilling bit to cut mortices for door locks and their face plates. It is quick and simple to set up, self centring and locks onto the door edge securely. It really is a simple process: mark the lock length on to the door, select the width of mortice cutter that suits your lock, set the depth collar, pass the drill shaft through the jig’s guide bush, lock the jig to the door and using power from your drill, drive the carbide tipped mortice